Natalie Cole died as a result of heart failure brought on by idiopathic pulmonary arterial hypertension (IPAH), her family said in a statement Thursday.

The singer died on New Year’s Eve at a hospital in Los Angeles at 65.

According to her family, Cole underwent a successful kidney transplant in 2009, after which she was diagnosed with IPAH.

“This is a very serious and progressive disorder,” her family said in the statement. “[Cole] responded well to PAH-specific agents over many years, during which she performed many concerts world-wide, but eventually succumbed to intractable right heart failure, an outcome that unfortunately commonly occurs in this progressive disorder, despite modern therapies.”

According to the website for the Mayo Clinic, pulmonary hypertension occurs when extra tissue forms in the pulmonary arteries, making it more difficult for the blood to flow and causing blood pressure to rise. When an underlying cause for the high blood pressure in the lungs can’t be found, the condition is considered to be IPAH.